Conventionally, to improve the power factor of an input current and to boost an output voltage, it has been proposed that a converter device that converts AC power into DC power use a booster circuit (so-called a power factor regulation circuit) consisting of a reactor, a reverse-blocking diode, and a switching element. Patent Literature 1 proposes a so-called interleaved power factor regulation circuit as an application of such power factor regulation circuit. That is, the power factor regulation circuit disclosed in Patent Literature 1 is a circuit that includes multiple booster sections coupled in parallel with one another, each consisting of a reactor, a reverse-blocking diode, and a switching element to allow the current path to branch, and that provides control to sequentially switch the switching elements of the respective booster sections, thereby enabling harmonic current to be reduced or eliminated.